1. Field of the Invention
The present invention relates to a stack-type lens array formed by stacking and bonding at least two lens sheets each having a plurality of lenses arranged on the plane and a lens module using the stack-type lens array.
2. Description of the Related Art
A lens module of a camera is mounted in a micro device, such as a mobile phone, and it is necessary to further reduce the size of the lens module. In general, a lens or a lens unit is provided with a light shielding member or an antireflection member in order to prevent defects, such as ghost or flare due to the reflection of light from a lens surface. This is similarly applied to a micro lens. However, in the micro lens, in many cases, the light shielding member or the antireflection member is directly formed as a light shielding film or an antireflection film on the lens by vapor deposition or coating.
A method has been proposed which manufactures a large number of lenses and lens modules at a time. JP2003-337206A discloses a stack-type lens array formed by stacking and bonding a plurality of lens sheets each having a plurality of lenses arranged on one sheet. A light absorbing film is formed at the boundary between the lenses. Concave grooves formed in four sides of the lens sheets are fitted to each other and the two lens sheets are positioned so as to overlap each other. The two lens sheets are fixed by adhesion pins which are inserted into pin insertion holes provided at four corners.
JP2009-279790A discloses a camera module with light receiving elements which is manufactured by overlapping two lens sheets each having a plurality of lenses arranged therein with a sensor substrate having a plurality of light receiving elements arranged thereon in the same pattern as the lenses and dicing the laminate into lenses. For each lens, an optical surface shape is transferred to a resin which is filled in an opening provided in a lens substrate by a mold and the opening serves as a diaphragm aperture.